Research Institute for Environment and Livelihoods, Charles Darwin University , Darwin, Northern Territory 0815, Australia.
The School of the Environment, The University of Queensland , Brisbane, Queensland 4072, Australia.
Philos Trans R Soc Lond B Biol Sci. 2024 Oct 21;379(1912):20220528. doi: 10.1098/rstb.2022.0528. Epub 2024 Sep 4.
How animals move and associate with conspecifics is rarely random, with a population's spatial structure forming the foundation on which the social behaviours of individuals form. Studies examining the spatial-social interface typically measure averaged behavioural differences between individuals; however, this neglects the inherent variation present within individuals and how it may impact the spatial-social interface. Here, we investigated differences in among-individual (co)variance in sociability, activity and site fidelity in a population of wild estuarine crocodiles, across a 10-year period. By monitoring 118 crocodiles using coded acoustic transmitters and an array of fixed underwater receivers, we discovered that not only did individual crocodiles repeatably differ (among-individual variation) in each behaviour measured but also in how consistently they expressed these behaviours through time (within-individual variation). As expected, crocodile activity and sociability formed a behavioural syndrome, with more active individuals being less sociable. Interestingly, we also found that individuals that were either more sociable or displayed greater site fidelity were also more specialized (lower within-individual variation) in these behaviours. Together, our results provide important empirical evidence for the interplay between spatial, temporal and social individual-level behavioural variation and how these contribute to forming behavioural niches. This article is part of the theme issue 'The spatial-social interface: a theoretical and empirical integration'.
动物的运动和与同种个体的联系很少是随机的,种群的空间结构构成了个体社会行为形成的基础。研究空间-社会界面的通常会衡量个体之间平均行为差异;然而,这忽略了个体内部存在的固有变异性,以及它如何影响空间-社会界面。在这里,我们在一个为期 10 年的时间里,研究了野生河口鳄鱼种群中社交性、活动性和栖息地忠诚度的个体间(共)方差差异。通过使用编码声发射器和一系列固定水下接收器来监测 118 条鳄鱼,我们发现,不仅个体在每个测量的行为中可重复地表现出差异(个体间变异性),而且它们在时间上表现这些行为的一致性程度也存在差异(个体内变异性)。正如预期的那样,鳄鱼的活动和社交性形成了一种行为综合征,活动较多的个体不太善于社交。有趣的是,我们还发现,更善于社交或表现出更高栖息地忠诚度的个体在这些行为上也更加专业化(个体内变异性较低)。总之,我们的研究结果为空间、时间和社会个体行为变异性之间的相互作用以及它们如何形成行为生态位提供了重要的经验证据。本文是主题为“空间-社会界面:理论和经验综合”的一部分。